Also generally I'd aim to have your fingertips on the French bow, rather than the half-grip pictured. More flexibility.
I was told in early days to put the bow on a flat surface, relax my hand and pick up the bow. The hold kinda dictates itself. The more finger joints you have free before the bow, the more flexibility hence the more fine control.
However, looking around images of the same, most people seem to do the half-grip, which is definitely easier.
I actually went to the dark side and now use a German grip bow, with which you get more power but far less flexibility. Seems to work for Gary Karr! ;-)